These early stages, however, are important for constraining models of high-mass star formation, which differ in their predictions for the formation pathways and mass ratios of young binary or multiple systems. Modelling the collapse of isolated massive prestellar cores including turbulence and radiative and outflow feedback, [1]} find that companion stars form via turbulent fragmentation at early times and via disk fragmentation at late times (while with a strong magnetic field, no companion stars are formed).
Other recent magnetohydronamic [2]} and hydrodynamic [3]} models of the collapse of massive cores indicate
that binaries form via disk rather than core fragmentation, with disk spiral arms playing an important role.
While the binary formed in the early radiation-hydrodynamic simulations of [4]} consists of two high-mass stars, many subsequent works [5]}, [6]}, [1]}, [8]} instead predict the formation of hierarchical systems with a single high-mass member.
Notable recent exceptions are the super-Alfvénic cases of [2]}, which form stable binary systems with mass ratios of \(\approx \) 1.1-1.6 and separations of a few hundred au.
